Spaceborne Observations of Lightning NO₂ in the Arctic

Abstract

The Arctic region is experiencing notable warming as well as more lightning. Lightning is the dominant source of upper tropospheric nitrogen oxides (NO x ), which are precursors for ozone and hydroxyl radicals. In this study, we combine the nitrogen dioxide (NO2) observations from the TROPOspheric Monitoring Instrument (TROPOMI) with Vaisala Global Lightning Dataset 360 to evaluate lightning NO2 (LNO2) production in the Arctic. By analyzing consecutive TROPOMI NO2 observations, we determine the lifetime and production efficiency of LNO2 during the summers of 2019–2021. Our results show that the LNO2 production efficiency over the ocean is ∼6 times higher than over continental regions. Additionally, we find that a higher LNO2 production efficiency is often correlated with lower lightning rates. The summertime lightning NO x emission in the Arctic (north of 70° N) is estimated to be 219 ± 116 Mg of N, which is equal to 5% of anthropogenic NO x emissions. However, for the span of a few hours, the Arctic LNO2 density can even be comparable to anthropogenic NO2 emissions in the region. These new findings suggest that LNO2 can play an important role in the upper-troposphere/lower-stratosphere atmospheric chemical processes in the Arctic, particularly during the summer.

Intraurban NO2 hotspot detection across multiple air quality products

“…However, since both observational datasets support its presence, an emission source may be missing in the underlying emissions data. Previous studies have used observational datasets to constrain NO x emissions (Goldberg et al 2022) and to identify specific NO 2 emission sources (Georgoulias et al 2020, Zhang et al 2023). However, low data coverage from TropOMI could impact the identification of the observational hotspot, particularly in the winter when meteorological conditions are not conducive to TropOMI observations.…”